yeah, if u do have an atmo venting blow off valve, try adjusting the screw on the top of it and see if that makes a difference. if the valve stays open too long it can make the car do that.
are you still running the standard air flow meter/computer?
Oils won't affect much until it's heavily modified...
IE: I use either Fuchs, Shell or Mobil oils. I also use Penrite.
Guys with heavily modded cars will run the ultra-expensive stuff like Motul, but i'm yet to see paperwork that proves they run any "better" or that it increases longterm engine life (considering a heavily modified engine has a short lifespan anyway)
the more you pay for oil, the better it is, i doubt that spending top dollar is necessary either, penrite, or any other big name oil is going to do a good job
ive just used the 4100 in my last il change about 500km ago.. lifter noise is still there, but it's not as loud or frequent as before.. give it a couple more km's and see what happens i guess.. also don't mean to plug em but philcom has some industrial lifter oil which has said to completely make the noise go away.. havent tried it myself but i will next oil change and see how that goes..